Radio systems have many modular electronics systems for providing radio communications to and from vehicles for example military vehicles and the like. The existing Ground Mobile Radio (GMR) Ground Vehicle Aerodynamics (GVA) was designed to accommodate modules such as power amplifiers, transceivers, and Platform Interface Modules (PIM). In such radio systems a Dual Integrated Core Engine Transceiver (DICE-T) or similar devices have strict requirements for system clock. The core engine modem and core engine RF in DICE-T utilizes 10 MHz reference clock from a Ground Vehicle Adapter (GVA) to meet Radio Frequency (RF) output requirements.
Referring to FIG. 1, simple clock distribution architecture 100 of a DICE-T module 108 in a radio system is disclosed. A 10 MHz reference signal 108 is supplied to a core engine modem 104 and a core engine RF 106 in DICE-T module 108 from GVA 102. The core engine modem 104 generates a noise signal which affects the reference clock signal of core engine RF 106 and hence affects the performance of RF circuits. By simultaneously sending the clock signal 108 to core engine modem 104 and core engine RF 106, the RF performance is reduced and spurious noise is increased. Also, the ADC and DAC in core engine modem receive fixed unchangeable frequency from GVA irrespective of waveform requirements. This increases the power consumption when high sample rates are not required.
A need, therefore, exists for an apparatus and method for improved clock distribution architecture in radio systems. Such apparatus and method should minimize the corruption of the reference clock to the RF circuitry by reducing phase noise of the reference clock signal. Also, the apparatus should allow RF card to change the frequency of the ADC and DAC clocks to the modem, depending upon the waveform requirements